Enterolert^®-DW from IDEXX, used for the enumeration of enterococci bacteria in water, has been granted the NF Validation by AFNOR Certification for bathing water (fresh and marine water samples) under the reference IDX 33/03-10/13, expanding the scope of the validation from its previous certification for drinking water. The Summary Report* can be found here – Summary Report.  

The first method to be validated by AFNOR for the detection of enterococci in drinking water, Enterolert-DW is a liquid culture method, which uses a defined substrate technology and incorporates a specifically designed blue background colour in its formulation. When the enzyme substrate is metabolised by enterococci, the sample turns from blue to green to indicate detection. Any change from the original colour to green is considered a positive result. No agar preparation is necessary, the reagent comes pre-weighed and contains no toxic compounds. Samples can be processed in less than 1 minute and confirmed results are available after 24 hours incubation at 41°C.

Quantification of bacterial contamination is undertaken using the IDEXX Quanti-Tray®, a specifically designed, multi-well plate. Once the water sample is collected, the pre-dosed powder is added to the sample container, then agitated and poured into the Quanti-Tray, which is then sealed to create a number of discrete cells where the reaction takes place when incubated. After 24 hours of incubation at 41°C, the number of wells which have changed colour to green are counted, and this is used to determine the level of contamination based upon the most probable number, or MPN, method.

Multiple comparative trials by European laboratories have shown Enterolert-DW to be superior to the ISO 7899-2 method for potable water testing, and compared to other culture methods, which typically take 48 hours to incubate, with a further confirmatory step, Enterolert-DW identifies potential contamination faster.

To learn more about Enterolert-DW visit IDEXX or email the company directly by using the Request Information button.

*The Summary Report presents the results of the extension validation study to achieve AFNOR ‘NF Validation’ for Enterolert®-DW and Quanti-Tray® or Quanti-Tray 2000®, developed by IDEXX for the enumeration of enterococci in drinking water intended for human consumption and fresh and marine bathing waters. The method was compared to the reference method NF EN ISO 7899-2 (August 2000) standard according to the general protocol of AFNOR Certification (rev 2 May 2013).